Reconsideration of Severe Hypoglycemic Events in the Treat-to-Target Trial

Objective: This article reevaluates the hypoglycemic episodes reported as severe in the Treat-to-Target Trial comparing insulin glargine and NPH insulin use in patients with inadequately controlled type 2 diabetes. Methods: Case report forms from the Treat-to-Target Trial were reviewed to identify additional severe hypoglycemic events and to further characterize those events already identified. Severe hypoglycemia was defined as symptoms consistent with hypoglycemia requiring assistance of another person and associated with either glucose levels <= 56 mg/dL or prompt recovery after oral carbohydrate intake, intravenous glucose administration, or glucagon injection. Results: This analysis confirmed that severe hypoglycemia was similarly uncommon with both insulins (insulin glargine [n = 367], nine patients, 14 events; NPH insulin [n = 389], nine patients, 13 events); all hypoglycemic events for glargine and nine for NPH were treated effectively at home. All severe hypoglycemic episodes were associated with sulfonylurea use. A review of case report forms demonstrated inconsistencies in identification of severe hypoglycemia (seven of 14 severe events for glargine and three of 13 severe events for NPH were coded as moderate). Conclusions: The rate of severe hypoglycemia in this trial was low. Difficulties in gathering and interpreting hypoglycemia data highlight the need for more objective methods.